you can set the level of logging that is available to your application. Basically, the logging in the servlet spec allows you to see differently grained versions of logging messages. You would set the logging ot quite high in development so that you find out at each step what is happening in your app. Once it goes into production you only want to see errors. In the old spec, you then checked the debug level: if(debug>0) debug("blah blah"); etc, etc